The work on this project is directed towards understanding cellular interactions which regulate immunoglobulin production and results in chronic suppression of production of certain immunoglobulins in young animals exposed perinatally to anti-immunoglobulin antibody. We hope results obtained in these studies will prove useful for specific understanding of the immune system and also perhaps in the treatment or prevention of human dysgammaglobulinemias and other diseases of the immune system. Specifically, we propose to study the following: 1. Identification, characterization, isolation and induction of cells and soluble factors active in the Ig-1b allotype regulatory network including: suppressor T cells (Ts); induction of Ts; soluble suppressive factor (TsF), helper T cells (Th); precursors and producers of Ig-1b allotype (B); other (as yet uncharacterized) regulatory cells; T cell clonal lines (fusion hybrids) expressing surface determinants or functional properties of regulatory cells in the network. 2. Description of mechanisms involved in the Ig-1b allotype regulatory network including: recognition, reception of signal and response. 3. Exploration of other chronic allotype suppression systems. 4. Development of congenic strains.